Head-up displays (also abbreviated below as HUDs) are known vehicular display devices. A HUD displays information regarding a vehicle state and a route by using images of figures containing numbers, characters, and arrows, for example.
For example, some vehicular HUDs form virtual images in front of a windshield as the above images, thereby providing these virtual images for a driver (refer to PTL 1). The HUD described in PTL 1 is an application example of a technique in which a screen scanned to form an image moves along an optical axis whereby a projected location of a virtual image varies. Herein, the projected location of a virtual image refers to a location of a virtual image in a depth direction as viewed by a driver and will also be referred to below as a display distance. By changing the projected location in this manner, the display distance can be varied with a running speed of the vehicle. This can prevent the driver from greatly moving his/her point of view during driving.